Governor cam-shaft brake



Dec. 4, 1923. l

. K. R. MANVILLE GOVERNOR zum.v SHAFTA BRAKE Filed belg. 1922 A TTOH/VE V5 l TED iras

KEITH-n. MANVILLE, or encontrar, NEW-YORK.. nssrenonmo 4INf'rnaamw:10NA1. Moron .coivrranr,v orfnnw Yoan, N. Y., A, conronn'rronOEDELAWARE.' l

GOVERNOR CAM-SHAFT BRAKE Application' ledvDiecember 7, 1922. "SerialNa 605,389.

To all who/mA 'it Ningbo/zwem.'

Be it known that I, KEITH R. MANVILLE, a citizen of the United States, residing in the borough of Brooklyn, of the city of-New 5 York, in the State of New' York, have invented certain new and 'useful Improvements in Governor Cam-Shaft Brakes, of which the following is a specification, reference being hadto the accompanying draw- ]0 ino, forming ,a part hereof.

` uring the operation of internal combustion engines at low speeds a cani shaft tends to drag and accelerate, at different speeds, depending upon whether thevalve spring is resisting its movement or retardi-ng it with the result that a .slap` is setup in thosegears where back-lash is provided. The object of the invention is to provide a brake forthe cam shaftwhich will co-operat-e therewith in such manneras to assist in maintaining constant angular speed atall times. More particularly, the invention seeks to provide a brake of this character whichshall be lcontrolled by the governor for the throttle valve so that its application will be v'most effective at low speeds and its release brought about at high engine speeds. A more particular object of the invention is to associate the improved devices with manually operated pressure relief devices of'conventional form to the end that certain of the elements thereof may be availed of in accomplishing the desired objects. For instance, it is usual in manually .operated pressure relief devices to include a spring pressed detent for maintainingthe cam shaft in predetermined axial positions. rIhis detent inthe improved devices mayfbe made of such construction aste-'automatically set up some braking eort on the cam shaft at all' speeds. Another element of the pressure relief devices which lmay be availed Since the invention, in its `broader` aspects, is not to be 'limited to the combination .of the improveddevices with vpressure relief mechanisnr the embodiment-will be describedfirst with reference only4 to a cam shaft brake Iand without regard to the relief mechanism with which may be' associated. This phase of the invention does coiit'emplate,however, .the yassociation with the braking element. ofxa governor control'. In the drawings a cam shaft a 'is illustrated as journaled yin a bracketfbt and driven through `a gear ai keyed atuone end and theshaft lbeing'shiftable `longitu-A dinally as willl-ater appear.v In the preferred construction the'shaft is journaledr` ina bushing o', which is flanged yat b-'toprovide a brak-ing surface of extenidedrarea for 'co-operation therewith of a'jeontactingiiange c of a bushing c carried rotatably withfthe shaft a. Provision forlubrieatingthe contacting surfaces oftheshaft and bushings is provided bythe oil duct VWhen the shaft za, is slid longitudinally it will lbecevidenttlrat greater Mor less brakingV effortmay be iinpressedthereen .through the engagement of the 0,55- Thisbrakingxefforttends to maintain the angular speed of theshaft constant at all times and particularly at low speeds where the valvespringassists.in accelerating itat periods. In the preferred embodiment: it is i proposedA to transmit brakingeffortto. the shoe@ through'an arm` al .engaged therewith andfcarried with a slida'ble rod d notched at Yfor engagement withv a spring pressed; detent e tapered at its end to exertconstantlya lateral'thrust ont-he rod and setup some braking effort vbetween the shoe cand the drum'v b2.: It is proposed, fat

ing effort through an additional spring the pressure of Vwhich is. automatically reduced 'through a governor at higliier engine speeds. Asfshoawn, a governor mechanism isl provided including Ia rrotating shaft which may b e driven operatively from. vthe crank shaft and on which iS feathered sleeve g adapted to tbe moved Aon the "Shaft lindert-he iniiuence of two governor weights 7 which are rotatable with the shaft f. A spring f2 normally tends to draw'the governor weights f together and centrifugal force throws them outwardly against the action of the spring f2 to move the sleevefg axially in a manner commonly employed. This governor may serven to control the throttle of the motor through a bell- Alower engine speeds tri-supplement this brakcrank 7L and link Vit', the bellcrank being Vpivoted on a shaft 7b2. On the shaft ZL? is shaft 71,2 to form a service arm'hs' adapted to engage the arm i Vwhen the bell-crank is rocked on the shaft and rock the arm i in a counterclockwise direction.V ln the Aillustrated embodiment an ear z" at one side of the arm cf is disposed lin the path of the arm h3 for engagement therewith when the bellcrank is thus rocked. Y

At lower engine speeds the full force of thespring 7c is transmitted through the arm 7l and the arm Z to the brake shoe c to retard the angular movement of the cam shaft a and thereby tend to maintain it constant. The action 'of the spring 7c is in 'addition to the constant thrust set up by the spring pressed'M detent e in the manner lhereinbefore described. At higher engine speeds the governor lweights 7 move outwardly and slide the sleeve g so as to rock the bellcrank 7L and through the arm k3` rotate the arm c' against the action of the spring k thereby relieving the pressure of the latter somewhat and diminish the braking action, as is desired. y

AV more specific object'ofthe present invention is to associate the improved devices with thel pressure reliefV mechanism in such manner as to use certain of the elements thereof in the combination. Pressure relief devices contemplate tlie association Vwith the exhaust cams such as a2 of an opposed cam section c3 thereon which no-rmally is I out of line with the valve stem indicated conventionally at Z but adapted to be brought into operative relation to the valve stem when the shaft a is slid longitudinally.

f Manual devices are ordinarily employed to Cil slide` the cam a to bring the cam section a3 Vinto operative relation to the valvey stem Z. Such manual devices may include an arm Z engaged with the shaft a in such mannerV as to permit rotation thereof but effectV longitudinal movement through the journal bearing b. The detent e may engage either one of two notches Z2 in the rod Zto maintain the shaft c in its two predetermined positions, one beingwith the cam section a3 out of operative relation with the valve stein Z and the other with the cam section a3 yin operative relation with the valve stem actuating the arm Z may include a bell-crank m engaged therewith and adapted to be moved through suitable linkage. i

It is believed that the scope of the invention andv its:` particular featuresvliaverbeen described with sufficient clearness herein but it is to be understood that latitude and matters vof design and arrangements oflparts. isopen to one skilled in the art.

What I claim is: l. A brake for a cam shaft includingr a drum' and a brake shoe -operatively disu-v posed to effect a braking action 'on the shaft,

so. y

GISKV a spring to set up a. braking pressureY be- Y 3. A brake for cam shafts includingin combination with a., slidable shaft a drum in which the shaft is journaled, ashoe rotatable with the shaft and adapted to cooperate with' said drum, an' arm through which the shaft is Ymoved to press the shoe against the drinn, a spring associated with the arm'to set up abraking pressure, and a governor to counteract the spring land reduce the braking pressure at higher speeds of the shaft. Y

4:. In combination with a slidable cam shaft and pressure relief mechanism for shifting the shaft, a spring pressed detent to maintain the shaft in predetermined axial positions, and a Vcam shaft brake operative to'retard the angular speed of the shaft said detent co-operating with said brake tonormally maintain a braking pressure.

5. In combination with a throttle control governor for an engine and a cam shaft, a brake co-operating with the cam shaft to retard its angular speed, a s pringoperatively engaged with the brake to exert its greatest braking pressure at lower speeds of Vthe cam shaft and means associated with the throttle governor to oppose Vthe action of at higher engine speeds.

This specification signed this 5th day of December A. D. 1922.

KEITH R; MANviLLE. 

